From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56B4AC31E57 for ; Mon, 17 Jun 2019 13:12:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 366152054F for ; Mon, 17 Jun 2019 13:12:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727892AbfFQNMj (ORCPT ); Mon, 17 Jun 2019 09:12:39 -0400 Received: from mout.kundenserver.de ([212.227.17.24]:53435 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725973AbfFQNMi (ORCPT ); Mon, 17 Jun 2019 09:12:38 -0400 Received: from threadripper.lan ([149.172.19.189]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.145]) with ESMTPA (Nemesis) id 1MTzKW-1i2oYx43MY-00QycG; Mon, 17 Jun 2019 15:12:14 +0200 From: Arnd Bergmann To: Andrew Morton Cc: Arnd Bergmann , Alexander Potapenko , Kees Cook , Christoph Lameter , Nick Desaulniers , Kostya Serebryany , Dmitry Vyukov , Sandeep Patil , Laura Abbott , Jann Horn , Marco Elver , Stephen Rothwell , linux-kernel@vger.kernel.org Subject: [PATCH] lib: test_meminit: fix -Wmaybe-uninitialized false positive Date: Mon, 17 Jun 2019 15:11:57 +0200 Message-Id: <20190617131210.2190280-1-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:kOJR4T41V/xJjVqo+3xT+Z4mWAd8aTQRzAFqh4zAFz0xLbWz96U 2dooLYqmY+E0WT/rDs/meig77BanZK7eoQzYy1zN5ZRAWt5HY7zV+cvn+EBlN/lXLuR/PA6 BVj9LTOouIEzed06XF+0wHwJ1dBmHryeKugsG28von18kBLDu1kF/aJ4vO1ydIL8zutGLO+ pkp6F7iWbM39bcEuGArFA== X-UI-Out-Filterresults: notjunk:1;V03:K0:IXykDVGcQ/g=:THSQ10OrLUrXEk6BhOe21s s0nGLPNWCfJHDuwD4FInvG63Xu3CGGen54eLAyQNRWko2f64iIVTPx2AWXm1Nh7fRJ+UI0LF3 HF8KA5+DMPyOAi3UQhZebphdh9T/etXNs21RyY/F8OMRHIbkCTATtqy241bgFcBcv7G0pwqq8 75M6c6ROVXpC7Hhzv5GzfuwAxOpBzIgQJMxxr39U+HS5JG2IyPiiut/FW4cR2msshVPR+bIso vsieTcMpldKIl4VHn/6/fyzpdUJ1PAPL5evBCun18Z1vVvFj8qY4csbn/l6+qbbQaR6yFSgII VKVugbsLHIAiywi5sTn4b0F4pngRTHTcBrRW6t0wnkzxllqqQyAfIK0soF7ZfOTSokRs2nowF sUX7THC/UKYIsW9ynnyj+hekdIyMNYkbQTbUQCH8tHGevkU2na6SUf6MrwLHhOlpK0KIi5Tq5 mU0IayF2qX1/BPVz5lM51QMBf6g1ZOOXd45T0tNd2OHf/CG/vYtB8QX2V+6tdZCC+7VXavbC4 CucNF62zDcwhFXH7UIotOioUmR6720c4U5zr7Q/O1+N4gSfLjLER9rEljqE1874xeoqonwWTI pwsIV44lcZ+8A0iTJTl3yB7AbCoP1KTo3YuhuazKOlkjFCq2EEpcM0fm2VwRnASZl+d2a0NZH qVHxk2/GiQW/FojsogBlrG+fLFdiutMKmS3ZGi5a1IqN7ePcSWncCsuHqK8Wjya5vxYYafrtA h8FZkhSYwqX2xvQZ/cntP2f5WhSdZcV3+Zqw2A== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The conditional logic is too complicated for the compiler to fully comprehend: lib/test_meminit.c: In function 'test_meminit_init': lib/test_meminit.c:236:5: error: 'buf_copy' may be used uninitialized in this function [-Werror=maybe-uninitialized] kfree(buf_copy); ^~~~~~~~~~~~~~~ lib/test_meminit.c:201:14: note: 'buf_copy' was declared here Simplify it by splitting out the non-rcu section. Fixes: af734ee6ec85 ("lib: introduce test_meminit module") Signed-off-by: Arnd Bergmann --- lib/test_meminit.c | 50 ++++++++++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 24 deletions(-) diff --git a/lib/test_meminit.c b/lib/test_meminit.c index ed7efec1387b..7ae2183ff1f4 100644 --- a/lib/test_meminit.c +++ b/lib/test_meminit.c @@ -208,35 +208,37 @@ static int __init do_kmem_cache_size(size_t size, bool want_ctor, /* Check that buf is zeroed, if it must be. */ fail = check_buf(buf, size, want_ctor, want_rcu, want_zero); fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0); + + if (!want_rcu) { + kmem_cache_free(c, buf); + continue; + } + /* * If this is an RCU cache, use a critical section to ensure we * can touch objects after they're freed. */ - if (want_rcu) { - rcu_read_lock(); - /* - * Copy the buffer to check that it's not wiped on - * free(). - */ - buf_copy = kmalloc(size, GFP_KERNEL); - if (buf_copy) - memcpy(buf_copy, buf, size); - } - kmem_cache_free(c, buf); - if (want_rcu) { - /* - * Check that |buf| is intact after kmem_cache_free(). - * |want_zero| is false, because we wrote garbage to - * the buffer already. - */ - fail |= check_buf(buf, size, want_ctor, want_rcu, - false); - if (buf_copy) { - fail |= (bool)memcmp(buf, buf_copy, size); - kfree(buf_copy); - } - rcu_read_unlock(); + rcu_read_lock(); + /* + * Copy the buffer to check that it's not wiped on + * free(). + */ + buf_copy = kmalloc(size, GFP_KERNEL); + if (buf_copy) + memcpy(buf_copy, buf, size); + + /* + * Check that |buf| is intact after kmem_cache_free(). + * |want_zero| is false, because we wrote garbage to + * the buffer already. + */ + fail |= check_buf(buf, size, want_ctor, want_rcu, + false); + if (buf_copy) { + fail |= (bool)memcmp(buf, buf_copy, size); + kfree(buf_copy); } + rcu_read_unlock(); } kmem_cache_destroy(c); -- 2.20.0